My thought of the stationary flywheel storage system is more for smoothing of the changing output of a large wind generation facility. Since most generators have to be spinning in order to supply power during any lulls, the more unstable any one generation source is, the more "cushion" one needs to absorb any transients.
I believe that Germany has an electric grid stability problem because a significant portion of their generation capacity is wind powered. When a weather front moves through the area, the ouput of the wind driven generation fluctuates significantly. These fluctuations can wreak havoc, especially under extreme load conditions.
Here in the 'colonies', our interconnect grid is so huge that variations in one geographical area can usually be offset by generation outside the affected area. Plus, at this time, wind is not a major generation source.
I agree that H2 generation is a load that doesn't really care about short term variations too much. Along the same lines, most pumped storage plans probably don't care either. However if wind is going to become a significant player in the grid connected generation, I believe that it would be VERY helpful to have it contribute to the stability of the grid, not unsettle it.
